Going on location feasibility

ABSTRACT

Techniques and devices to assist an offshore unit in going on location and coming off location. A device may include an interface configured to receive a signal indicative of motions of an offshore unit. The device may also include a memory configured to store a set of values corresponding to acceptable motions of the offshore unit, as well as a processor configured to determine if a measured motion of the offshore unit exceeds at least one value of the set of values and generate an indication that going on location by the offshore unit can be undertaken when the processor determines that the measured motion of the offshore unit is less than or equal to the at least one value.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Non-Provisional Application claiming priority toU.S. Provisional Patent Application No. 62/209,407, entitled “UsingOnboard Sensor Data to Assess Feasibility of Jackups to go on Location”,filed Aug. 25, 2015, which is herein incorporated by reference.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

This invention relates to mobile offshore units, specificallyself-elevating units. Self-elevating units are used in the offshoreindustry for a multitude of tasks including but not limited to drillingand production operations, general construction operations, crewaccommodation, wind-turbine installation, etc. Self-elevating units canrefer to jackups, liftboats, jackup barges, mobile offshore drillingunits (MODUs), mobile offshore production units (MOPUs), or the like.

Self-elevating units (henceforth referred to as “units”) are typicallyconstructed of a hull, supported on one or more legs which extendthrough or on the side of the hull. A lifting system or “jacking system”is installed on the unit for the purpose of raising or lowering the legsrelative to the hull. The self-elevating unit is designed such that thehull is buoyant and can float, supporting itself and the legs and itscargo (e.g., in an “afloat” mode). Once the self-elevating unit reachesthe desired location where it is to operate, the legs are lowered to theseabed and the hull is raised above the waterline (e.g., in an“elevated” mode), so that there is no longer a buoyancy force on thehull, creating a stable platform with a positive airgap. One of thefirst steps in the process of transitioning from afloat to elevated modeis commonly referred to as “going on location.”

Conversely, the process of transitioning from elevated mode to afloatmode is commonly referred to as “coming off location.” Theself-elevating unit lowers its hull from positive air gap into thewater, partially submerging the hull. The jacking system lowers the hulluntil the buoyancy of the hull is sufficient to extract and raise thelegs. The legs of the self-elevating unit typically incorporate afooting that provides the bearing or contact surface between the seabed(and/or the soil beneath the seabed) and the unit. The legs of aself-elevating unit may have an individual footing for each leg(spudcan) or the legs may share a common footing (mat).

Analysis of units in the elevated and afloat modes is fairly wellunderstood, and standards exist for use in the development of properoperating conditions for both modes of operation. The transition phasefor self-elevating units (e.g., going on location or coming offlocation), however, is not as well understood.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a profile view of a self-elevating unit in the afloatmode;

FIG. 2 illustrate a profile view of a self-elevating unit in theelevated mode;

FIG. 3 illustrates a profile view of a self-elevating unit during thetransition segment from afloat to elevated mode;

FIG. 4 illustrates a profile view of a self-elevating unit making impactwith the seabed during the transition segment from afloat to elevatedmode;

FIG. 5 illustrates a schematic of a control system of a self-elevatingunit;

FIG. 6 illustrates a flow chart of operation of the control system ofFIG. 5;

FIG. 7 illustrates a representative screen shot of a displayillustrating combined motion statistics with allowable criteria to beused in making a decision for going on location;

FIG. 8 illustrates a second representative screen shot of a display foruse in making a decision for going on location;

FIG. 9 illustrates a third representative screen shot of a display foruse in making a decision for going on location; and

FIG. 10 illustrates a fourth representative screen shot of a display foruse in making a decision for going on location.

DETAILED DESCRIPTION

One or more specific embodiments will be described below. In an effortto provide a concise description of these embodiments, all features ofan actual implementation may not be described in the specification. Itshould be appreciated that in the development of any such actualimplementation, as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments, the articles “a,”“an,” “the,” and “said” are intended to mean that there are one or moreof the elements. The terms “comprising,” “including,” and “having” areintended to be inclusive and mean that there may be additional elementsother than the listed elements.

Self-elevating units (which may be referred to as “units”) can refer tojackups, liftboats, jackup barges, mobile offshore drilling units(MODUs) (e.g., a platform equipped with a drill rig to engage inoffshore oil and gas exploration and/or equipped with maintenance orcompletion items to engage in work including, but not limited to, casingand tubing installation, subsea tree installations, and well capping),mobile offshore production units (MOPUs), mat rigs, or the like. Whilecalm conditions are desirable while conducting going on locationoperations, most of the time these operations are carried out in thepresence of waves which induce motions on the unit. These wave-inducedmotions cause the legs to impact the seabed. The degree of impact loadon the leg(s) is related to the waves, the soil properties, spudcanshape and the relative timing of jacking. Thus, during the “going onlocation” phase of a unit, the motions of the unit while afloat cancause severe loading of the legs as they impact the seabed. Typicallythe personnel responsible for the installation of the unit would usetheir best judgement and experience to estimate the sea-state andmotions of the unit when determining whether a unit can begin going onlocation operations (e.g., transitioning from afloat mode in which thelegs of the unit are not coupled to the seabed to elevated mode in whichthe legs of the unit are coupled to the seabed). However, the presentinvention allows for monitoring of conditions that impact going onlocation by the unit and/or may control the process of going on locationaccordingly. In this manner, a decision to install the unit on theseabed (e.g., going on location with the unit) may be made with greaterinformation than previously available and/or utilized. In someembodiments, one or more onboard instruments may be utilized in thedetermination of whether it is feasible (e.g., appropriate) to installthe unit onto the seabed based on, for example, prevailing conditions atsea.

For example, onboard instrumentation can be used to determine themotions of the unit, thus eliminating determinations of a specific seastate (e.g., dominant wave height, period, direction, and/or whether thewave is swell-dominated or wind-driven dominated). For example, motionof the unit may be measured by one or more onboard sensors, and the datacollected may be analyzed to provide a comparison of the unit's motionsagainst the acceptable values. Determinations of whether it isappropriate for the unit to go on location may then be made based uponthe analyzed data.

With the foregoing in mind, FIG. 1 illustrates an offshore platformcomprising a self-elevating unit 2 (which may be referred to as a unit2). Although the presently illustrated embodiment of an offshoreplatform is of a particular offshore self-elevating unit 2, otheroffshore platforms may be substituted for the self-elevating unit 2. Thetechniques and systems described below are described in conjunction withself-elevating unit 2 and are intended to cover at least jackups,liftboats, jackup barges, mobile offshore drilling units (MODUs), mobileoffshore production units (MOPUs), mat rigs, or the like.

The present unit 2 may include one or more systems that allow for agoing on location analysis of the unit 2. The one or more systems mayutilize onboard motion data to assist in the decision as to whether theconditions for installing the unit 2 on location are acceptable and/orcontrol the going on location of the unit 2. The self-elevating unit 2includes one or more legs 4 and the unit 2 is capable of floating on abuoyant hull 6, which may also operate to support the legs 4 of the unit2. As illustrated in FIG. 1, the unit 2 is operating in an afloat modeas its mode of operation, whereby the unit 2 has its legs fully raisedrelative to the waterline 8 above a seabed 10.

Technically speaking, FIG. 1 shows the unit in the afloat mode with itslegs fully raised (as it is also in the afloat mode when the legs arenear the seabed, as long as the legs never touch the seabed). Asdescribed in this paragraph, it is more like a “transit” mode ratherthan just an “afloat” mode. Of course, in order to be able to transit,the unit must be floating.

As illustrated in FIG. 2, the legs 4 of the unit 2 are able to belowered onto the seabed 10 so that the unit 2 and the hull 6 may beraised above the waterline 8 so that the unit 2 may operate as a stableplatform. This mode of operation is considered an elevated mode. Whilein the elevated mode, footings 12 (e.g., spudcans or the like) at thebottom of the legs 4, provide a bearing surface for transmitting loadsbetween the unit 2 and the seabed 10.

The initial process of transitioning from an afloat mode to an elevatedmode of a unit 2 is commonly referred to as “going on location” and isillustrated as a transition segment (e.g., a going on location segment)in FIG. 3. As illustrated, during a going on location operation of aunit 2, there is a time between when the legs 4 are lowered to makecontact with the seabed 10 and the time at which all legs 4 remain incontact with the seabed 10 and the draft of the hull 6 begins todecrease due to jacking of the hull 6. Moreover, as illustrated in FIG.4, during the transition segment of operation (e.g., while the unit 2 isgoing on location), impact loads 14 can occur on the footings 12, forexample, due to motions 16 of the unit 2. These impact loads 14 canpotentially cause damage and, thus, acceptable limits for going onlocation and installing the unit 2 at a given location on the seabed 10should be determined (e.g., determining whether motions 16 exceed one ormore levels, which may indicate a likelihood of an excessive impact load14 if the unit 2 begins to go on location when these motions 16 areobserved).

In one embodiment, at least one sensor 18 and a control monitor 20 maybe utilized as a control system 22 to allow for determinations ofwhether a unit 2 is able to go on location. Additionally, in someembodiments, the control system 22 may also control at least a part ofthe going on location transitioning of the unit 2. The control system22, made up of at least one sensor 18 and the control monitor 20, mayoperate to, for example, determine if the unit 2 is within thepredetermined acceptable operating limits for installing the unit 2 onlocation by combining and/or comparing of onboard motion data (e.g.,measured and transmitted by the sensor 18 to the control monitor 20)with the acceptable criteria. Based on this measured onboard motiondata, actual response information (e.g., measured motion) of the unit 2in response to, for example, environmental conditions may be generatedto allow for greater precision in determining the feasibility of goingon location at any particular time in real time or near real time (e.g.,based on currently measured motion data of the unit 2 by the sensor 18).

FIG. 5 illustrates an embodiment of the control system 22 inclusive ofthe sensor 18 and the control monitor 20. The sensor 18 may berepresentative of one or more motion detection sensors such as agyroscope, an accelerometer, or the like and the sensor 18 may measurethe motion of the unit 2, for example, in response to environmentalfactors (e.g., waves and/or currents affecting the unit 2). The sensor18 may be disposed on, for example, the hull 6, one or more legs 4,and/or one or more footings 12. The sensor 18 may operate to measure themotion of one or more portions of the unit 2 and transmit the measureddata to the control monitor 20 along path 24 for use by the controlmonitor 20 in determining whether the unit 2 may go on location. Path 24may be a hardwired connection or a wireless connection and reception ofthe measured data along path 24 will be described below in greaterdetail.

In some embodiments, the control monitor 20 illustrated in FIG. 5 may bea computing system, such as a general purpose or a special purposecomputer. For example, the control monitor 20 may include a processingdevice 26, such as one or more application specific integrated circuits(ASICs), one or more processors, or another processing device thatinteracts with one or more tangible, non-transitory, machine-readablemedia (e.g., memory 28) of the control monitor 20 that collectivelystores instructions executable by the processing device 26 to performthe methods and actions described herein. By way of example, suchmachine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM orother optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which can be accessed by the processing device 26.

Thus, the control monitor 20 may include a processing device 26 that maybe operably coupled with the memory 28 to perform various algorithms. Inthis manner, programs or instructions executed by the processing device26 may be stored in any suitable article of manufacture that includesone or more tangible, non-transitory computer-readable media at leastcollectively storing the instructions or routines, such as the memory28. Additionally, the control monitor 20 may include a display 30 thatmay be a liquid crystal display (LCD) or another type of display thatallows users to view images generated by the control monitor 20. Thedisplay 30 may include a touch screen, which may allow users to interactwith a graphical user interface of the control monitor 20. Likewise, thecontrol monitor 20 may additionally and/or alternatively transmit imagesto a display of an additional control device, for example, a separatecontrol monitor of the unit 2.

The control monitor 20 may also include one or more input structures 32(e.g., one or more of a keypad, mouse, touchpad, touchscreen, one ormore switches, buttons, or the like) to allow a user to interact withthe control monitor 20, such as to start, control, or operate agraphical user interface (GUI) or other applications running on thecontrol monitor 20. As may be appreciated, a GUI may be a type of userinterface that allows a user to interact with the control monitor 20and/or the control system 22 through, for example, graphical icons,visual indicators, and the like. Additionally, the control monitor 20may include network interface 34 to allow the control monitor 20 tointerface with various other electronic devices. The network interface34 may include a Bluetooth interface, a local area network (LAN) orwireless local area network (WLAN) interface, an Ethernet connection, orthe like. As illustrated, the network interface 34 may be coupled topath 24, in part, to receive the measured data from sensor 18 and thenetwork interface 34 may operate to transmit the received data to theprocessing device 26.

As will be described in greater detail below, the measured data receivedfrom the sensor 18 may be utilized by the control monitor 20 to generatean alarm that may, for example, be displayed on display 30 to indicatethat going on location should not be undertaken. For example, thecontrol monitor 20 may receive data from the sensor 18 and may utilizethe received data in conjunction with predetermined and/or pre-storedvalues to identify and display whether the unit 2 may proceed with goingon location, display operational limits for the unit 2 to go onlocation, display values indicative of how close to the currentenvironmental conditions affecting the unit 2 are to the operationallimits, display trends in the current conditions of the unit 2 withrespect to previously received data, and/or initiate or control thegoing on location operation of the unit 2. Some or all of thisinformation may be calculated and/or displayed on the display 30.

An example of a methodology for incorporating rig motion data fromonboard instrumentation into a going on location decision for a unit 2may be generally illustrated in the flow chart 36 of FIG. 6. In step 38,onboard instrumentation (e.g., sensor 18) may be utilized to obtain thedata indicative of motions of the unit 2. This data, in step 40, may betransmitted, for example, to the control monitor 20 for determination ofmotion of the unit 2 based on the received data. The determination ofthe motion of the unit may include, for example, processing of thereceived data from the sensor 18 to produce motion data that can be usedto determine one or more angular motion components, (θ_(x), θ_(y),θ_(z)), one or more angular velocities (e.g., three angular velocitycomponents, ({dot over (θ)}_(x), {dot over (θ)}_(y), {dot over(θ)}_(z))) and/or one or more translational accelerations (e.g., threetranslational acceleration components, ({umlaut over (x)}, ÿ, {umlautover (z)})). The one or more angular motion components, one or moreangular velocity components and/or the one or more translationalacceleration components may be utilized to determine statistics ofinterest. The determined statistics (e.g., the determined set of derivedstatistics of interest) based upon the data received from the sensor 18(e.g., indicative one or more onboard motion sensors) may be used todetermine the motion at each of the footings in step 42. For example,based on the determined motion of the unit, motion at each of thefootings 12 may be determined by the control monitor 20, for example,over a series of specified time intervals in step 42. In step 44,acceptable criteria (illustrated in step 46 as being previously and/orsimultaneously calculated and stored in the control monitor 20 or asbeing received and stored at the control monitor 20, for example, fromcloud based or other external storage device) may be compared againstthe motion of the unit 2 and/or the footings 12. This comparison in step44 may include a comparison of critical statistics against theappropriate permissible curve, for example, based on the soil conditionsand/or water depth. For example, the critical statistics may be comparedagainst the permissible curves to aid in the decision for going onlocation of the unit 2 in step 44.

The acceptable criteria from step 46 may be generated through the useof, for example, a non-linear time-domain response analysis combinedwith structural and diffraction analyses. The analyses undertaken togenerate the acceptable criteria (e.g., critical statistics which may becompared against the current data calculated in step 44) may utilize,for example, water depth, seabed 10 soil conditions, leg-seabedinteractions, jacking speed, footing 12 shape, jacking system stiffnessand/or the structural capacity of the legs 4, hull 6, and/or the jackingsystem of the unit 2. The analyses may generate one or more acceptablecriteria in step 46 for permissible wave height and/or rotation anglecurves vs. period curves for different units 2 at specified sets ofwater depth, wave direction, and soil conditions. The permissible waveheight curves can be achieved by iteration to identify the maximum waveheight that produces acceptable structural utilization ratios for all ofthe various critical components (e.g., critical statistics). Generally,analyses using regular waves may be applied by the control monitor 20when swells are dominant while analyses using random waves may beapplied by the control monitor 20 when wind-driven waves are dominant,which can be determined and entered/selected manually by a user orautomatically by the control monitor based on the sensor 18 datareceived.

Additional factors that may be utilized in step 46 to determinepermissible going on location information may include determinationand/or application of impact load on the unit 2, which is absorbed aspotential spring energy and may differ from the amount of pre-impactkinetic energy. Additionally and/or alternatively, rotational velocityas well as heave of a unit 2 may be utilized in step 46 to determine(e.g., calculate) permissible wave height curves which account for heaveand rotation effects. For example, impact load, while related tovertical velocity of the footings 12 prior to impact, is also a functionof period, and this is attributable to phase angle effects and thedegree to which the vertical motion of the footings 12 is due to heaveor rotation (pitch or roll). Accordingly, acceptable criteria curves maybe obtained in step 46 by iterating on wave height to find the limitingvalue that causes any of the structural limits of the unit 2 to reachits allowable capacity. These criteria curves predetermined for a unit 2of the type of unit that is going on location may be stored, forexample, in the control monitor 20 for use in step 44.

Given the possible sea-state make up and associated response, in step48, display of the results of the comparison may be made, for example,to make a proper recommendation for installing the unit 2. For example,analytical results generated based on the comparison in step 46 may beused to provide a statistical exceedance probability that may bedisplayed in step 48, for example, on the display 30 or transferred, forexample, via the network interface 34 for display on another display inthe unit 2 and/or at a location remote from the unit 2 (e.g., a remotemonitoring center). The display of information may include the displayof the statistics in such a way that the user easily discerns thedominant response and/or the variations in the response, as well astrends over time (e.g., current statistics moving towards or away fromcritical statistic levels). Furthermore, by displaying significant andmaximum values (e.g., critical statistics), the response can beclassified as wind-driven wave dominated or swell dominated.

One example of the displayed information in step 48 may include agenerated plot 50 as illustrated in FIG. 7. The plot 50 illustrates thestatistics of the processed onboard motion data 52 (e.g., from step 42)against the acceptable criteria curves 54 (e.g., from step 46) for agiven parameter (i.e., angles, velocity, etc.) as the output of step 44.This plot may include, for example, associated maximum values (as theacceptable criteria curves 54) and significant values 56 of theparameter criteria in wind-driven dominated conditions, and in swelldominated conditions. Additionally, parameter groupings, or bins,related to monitored periods may be classified as wind-driven or swelldominated, and assigned a utilization ratio after comparing thesignificant or maximum value to the appropriate permissible value, orlimit. Additional information provided to a user may include a histogram58 and utilization ratio statistics 60 that may also be of use indetermining whether or not to go on location with a unit 2.

The example plot 50 shown in FIG. 7 is intended to convey to the userhow close the unit 2 is to the defined acceptable criteria values 54,based on the derived statistics from the onboard instrumentation outputdata from sensor 18. This information can then be used in determiningwhether a unit may be installed (e.g., whether the unit 2 may go onlocation). By incorporating the motion statistics from data of thesensor 18 with the acceptable criteria generated in step 46 and appliedin step 44, improved determinations of the feasibility of going onlocation may be made. Additional embodiments include utilizing a singleset of limiting values as the allowable criteria for going on location,whereby the single set is selected as representative of the most onerouscondition (i.e., the most conservative). A determination may be made bythe control monitor 20 (and an indication thereof may be generated) thatgoing on location by the unit 2 should be undertaken when, for example,the processor 26 determines an amount of motion (or other determinedvalue) of the unit 2 is less than or equal to at least one value (e.g.,one or more sets of limiting values as the allowable criteria for goingon location, which may be selected as representative of the most onerouscondition). Likewise, a determination may be made by the control monitor20 (and an indication thereof may be generated) that going on locationby the unit 2 should not be undertaken when, for example, the processor26 determines an amount of motion (or other determined value) of theunit 2 is greater than or equal to at least one value (e.g., one or moresets of limiting values as the allowable criteria for going on location,which may be selected as representative of the most onerous condition).

Turning to FIG. 8, a representative screen shot of a graphical userinterface (GUI) 62 of a display 30 for use in conjunction with making adecision for going on location is illustrated. The GUI 62 may includeone or more user interactive tabs 64, 66, 68 that allow for a user tointeract with the program of the control system 20 executing one or moreof the steps illustrated in FIG. 6. For example, a first tab 64 mayindicate to a user that the control monitor 20 is available to receiveinput values 70, 72, and 74 from a user (e.g., via one or more inputstructures 32 or via a touchscreen) to control the GUI 62. These inputvalues 70, 72, and 74 may operate to initialize the control system 22 sothat the control system 22 is set up for operation in the correctenvironment. The information entered via input values 70, 72, and 74 mayalso be used by the control monitor 20 to, for example, filter and/orselect acceptable criteria from step 46 of FIG. 6, so that the correctvalues of acceptable data are applied by the control monitor 20 duringthe determination of the acceptability of going on location by the unit2.

As illustrated, input value 72 corresponds to an apparent soil stiffnessvalue related to the relative properties of the seabed 10 (e.g., thecomposition of the seabed 10). Input value 72 corresponds to a waterdepth (e.g., the depth of the water from the waterline 8 to the seabed10) and input value 74 corresponds to the leg position (e.g., theposition of a footing 12 of a leg 4 below the baseline of the hull 6).It should be noted that input value 74 may correspond to, for example,an input for multiple leg 4 position values, a single (e.g., average)position value for all legs 4, and/or independent inputs for one or moreleg 4 position values, which may be of use when different legs 4 haveone or more different positions (e.g., vertical heights). While inputvalues 70, 72, and 74 are illustrated in FIG. 8, it is appreciated thata fewer number or a greater number of input values may be displayed inconnection with the GUI 62. Additionally and/or alternatively, otherconditions separate from or in addition to those described above maycorrespond to the input values 70, 72, and 74.

Operational inputs 76, 78, and 80 may also be present in the GUI 62.Operational input 76 may correspond to a start recording input that willbegin the process of tracking and/or recording data from the sensor 18by the control monitor 20. This start recording operational input 76 mayinitiate a recording interval of a predetermined amount of time or itmay initiate a user-selectable recording interval. Operational input 78may correspond to a stop recording input that will halt the process oftracking and/or recording data from the sensor 18 by the control monitor20. This stop recording operational input 76 may interrupt a recordinginterval of a predetermined amount of time or it may terminate auser-selectable recording interval. Also illustrated is a post processoperational input 80 that may initiate processing of the recorded data(e.g., step 44 of FIG. 6). While operational inputs 76, 78, and 80 areillustrated in FIG. 8, it is appreciated that a fewer number or agreater number of operational inputs may be displayed in connection withthe GUI 62. Additionally and/or alternatively, other operational inputsseparate from or in addition to those described above may correspond tothe operational inputs 76, 78, and 80.

FIG. 9 illustrates a representative screen shot of the GUI 62 when theinteractive tab 66 is selected. As illustrated, one or more motion plots82, 84, and 86 are displayed in response to the selection of interactivetab 66. As illustrated, motion plot 82 may correspond to the heaveacceleration of the unit 2 as measured by the sensor 18 and/orcalculated by the control monitor 20 based on sensed data received fromthe sensor 18. Similarly, motion plot 84 may correspond to the pitchrate of the unit 2 as measured by the sensor 18 and/or calculated by thecontrol monitor 20 based on sensed data received from the sensor 18.Likewise, motion plot 86 may correspond to the roll rate of the unit 2as measured by the sensor 18 and/or calculated by the control monitor 20based on sensed data received from the sensor 18. Each of motion plots82, 84, and 86 may display data related to the motions of the unit 2and/or a portion of the unit 2 over time (e.g., over a predeterminedrecording interval and/or over a current recording interval that mayhave been initiated via operational input 76). In this manner, themotion plots 82, 84, and 86 may represent currently monitored/senseddata. Alternatively, the motion plots 82, 84, and 86 may representpreviously monitored/sensed data that is available for review by a userupon selection of the interactive tab 66. Additionally, while motionplots 82, 84, and 86 are illustrated in FIG. 9, it is appreciated that afewer number or a greater number of motion plots (or other types ofmonitored data plots) may be displayed in connection with the GUI 62.Additionally and/or alternatively, other motion plots (or other dataplots) separate from or in addition to those described above maycorrespond to the motion plots 82, 84, and 86.

FIG. 10 illustrates a representative screen shot of the GUI 62 when theinteractive tab 68 is selected. As illustrated, the GUI 62 includes agraphical representation 88 and status indicators 90, 92, 94, 96, and98. The graphical representation 88 may illustrate, for example,downward spudcan velocity (e.g., the velocity of one or more footings 12during an interval of time) as a visual indication of motion of thefooting 12. It should be noted that the graphical representation 88 ofdownward spudcan velocity is not the only representation that may bepresent in the graphical representation 88. For example, rotationalacceleration of the unit 2 or additional measured motions of the unit 2may be represented via the graphical representation 88 in addition to orin place of the downward spudcan velocity. The graphical representation88 may further include a legend 100 that identifies various plots (e.g.,by color, thickness, or another visual indicator) for the user to betterdifferentiate measurements represented in the graphical representation88. The interactive tab 88 and the GUI 62 represented therein maycorrespond to selection of the operational input 80 and/or the resulttransmitted in step 48 of FIG. 6.

As noted above, the GUI 62 in FIG. 10 may also include status indicators90, 92, 94, 96, and 98. Status indicator 90 may, for example, display anindication of how close a measured parameter is to a critical parametervia a ratio (e.g., a ratio of the motion of the unit 2 or a portionthereof against an acceptable criteria value). The indication in statusindicator 90 may be selected by the control monitor 20 or a user torepresent the measured parameter that is closest to its relevantacceptable criteria. Status indicator 92 may, for example, display anindication of the downward spudcan velocity of a footing 12 as measuredagainst an acceptable criteria. Likewise, status indicator 94 may, forexample, display an indication of a period (e.g., an oscillation periodof the response of the unit 2 due the presence of the waves or thelike). The indication in status indicator 94 may be selected by thecontrol monitor 20 or a user to represent the measured period that isclosest to its relevant acceptable criteria. Additionally, statusindicator 96 may, for example, display an indication of which leg 4 isexperiencing the most motion, is closest to its respective acceptablecriteria, or is closest to the seafloor 10, or the like. The indicationin status indicator 96 may be selected by the control monitor 20 or auser.

In addition to the status indicators 90, 92, 94, and 96, the controlmonitor 20 may generate an indication of whether the measured motionsare acceptable, as represented by status indicator 98. The GUI 62 may,thus, represent whether conditions are acceptable to go on location viathe status indicator 98, which may include text, color, or anotherindicator to provide positive or negative feedback as to whether theunit 2 can go on location. Auditory indications may also accompany thestatus indicator 98 to further aid in recognition of the feasibility ofgoing on location. Additionally, the indicator 98 may indicate thatautomatic control and/or deployment of the legs 4 has begun in a goingon location operation, if the process of going on location is automatedand/or mechanically controlled. In addition to generating andtransmitting a signal that controls status indicator 98, the controlsystem 22 may control the automated going on location of the unit 2either directly (e.g., via generation and transmission of one or morecontrol signals) or via transmission of a start signal or anauthorization signal to a jacking system of the unit 2, for example, tocontrol or to be utilized in the control of the jacking system and/or asa safety control of the jacking system. Additionally, the control system22 may determine if and which leg 4 is moving at a greater rate towardsto seafloor 10 and generate a signal to identify that leg 4 and/orcontrol the rate of descent of the identified leg 4 and/or the remaininglegs 4 to counteract the detection of the rate differential.

The present embodiments may alleviate potential issues that may arise onself-elevating units 2, wherein rotations are determined manually fromreadings on a bubble inclinometer (which may lead to erroneous andinconsistent readings due to, for example, user and/or instrumenterrors). Further errors resulting from bubble readings affected (e.g.,exaggerated) by inertia when the oscillation periods are small may alsobe reduced and/or eliminated through the use of the control system 22.Additionally, acceptable criteria for going on location may be set bythe environment, or the allowable sea-state, and typically is defined bywave height. Because the motions of the unit 2, and thus, the footings12, are determined by the control system 22, assumptions regarding waveexcitation load and other hydrodynamic coefficients as part of adiffraction analysis may be avoided, since actual motions of the unit 2are measured. Likewise, separate criteria for going on location may bebased upon whether waves are regular or random. To use the criteriaproperly (either the criteria for regular or random waves), adetermination of whether the sea-state is made up of swells, typicallyrepresented by regular waves, or wind-driven waves, typicallyrepresented by random waves should be made. Moreover, in a majority oflocations, both swells and wind-driven waves are present, making itdifficult to determine the proper criteria for installing the unit 2.However, through use of the control system 22, and more specifically,the use of the data gathered by sensor 18 related to the motions of theunit 2, the issues related to choosing of the correct criteria may bereduced by a more accurate criteria selection, since the motions of theunit 2 due to swells and/or wind-driven waves may be more accuratelymeasured and compared to the theoretical values, or the sea state maynot be a consideration at all as only resulting motions of the unit 2are of consequence to the control system 22.

It should be noted that the one or more sensors 18 may also include oneor more environmental sensors that are able to measure metocean (e.g.,meteorology and (physical) oceanography) conditions. This data may beused separately from (e.g., independently of) or in combination with(e.g., in parallel with) the motion data of the unit 2. For example, adetermination may be made by the control monitor 20 (and an indicationthereof may be generated) that going on location by the unit 2 should beundertaken when, for example, the processor 26 determines that an amountof motion (or other determined value) of the unit 2 is less than orequal to at least one value (e.g., one or more sets of limiting valuesinclusive of metocean data as the allowable criteria for going onlocation, which may be selected as representative of the most onerouscondition). Likewise, a determination may be made by the control monitor20 (and an indication thereof may be generated) that going on locationby the unit 2 should not be undertaken when, for example, the processor26 determines an amount of motion (or other determined value) of theunit 2 is greater than or equal to at least one value (e.g., one or moresets of limiting values inclusive of metocean data as the allowablecriteria for going on location, which may be selected as representativeof the most onerous condition). This determination inclusive of metoceanmay be performed as a separate set of steps similar to those outlined inFIG. 6 (e.g., steps 38, 44, 46, and 48 of FIG. 6 may be performed usingsensed metocean data separate from motion data in a manner similar tothat described above with respect to FIG. 6) either in parallel with thesteps performed in FIG. 6, in series with the steps performed in FIG. 6,or in place of the steps performed in FIG. 6 with respect to measuredmotion data.

Likewise, use of one or more environmental sensors as sensor 18 that areable to measure metocean conditions can be used when the unit 2 iscoming off location (e.g., transitioning from an elevated mode to anafloat mode). Prior to initiating the coming off location transition,the unit 2 may use the sensor 18 to obtain data indicative of metoceanconditions. This data may be transmitted, for example, to the controlmonitor 20 for determination of metocean conditions based on thereceived data through, for example, generation of statistics ofinterest. These statistics of interest may be compared againstacceptable criteria (which may be previously and/or simultaneouslycalculated and stored in the control monitor 20 or may be received andstored at the control monitor 20, for example, from cloud based or otherexternal storage device). This comparison may include a comparison ofcritical statistics against one or more appropriate permissible curvesto aid in the decision for coming off location.

Given the comparison, display of the results of the comparison may bemade, for example, to make a proper recommendation for whetherconditions are favorable for coming off location. For example,analytical results generated based on the comparison may be used toprovide a statistical exceedance probability that may be displayed, forexample, on the display 30 or transferred, for example, via the networkinterface 34 for display on another display in the unit 2 and/or at alocation remote from the unit 2 (e.g., a remote monitoring center). Thedisplay of information may include the display of the statistics in sucha way that the user easily discerns the dominant response and/or thevariations in the response, as well as trends over time (e.g., currentstatistics moving towards or away from critical statistic levels). Bycomparing the metocean data of the sensor 18 with acceptable criteria,improved determinations of the feasibility of coming off location may bemade. Additional embodiments include utilizing a single set of limitingvalues as the allowable criteria for coming off location, whereby thesingle set is selected as representative of the most onerous condition(i.e., the most conservative). A determination may be made by thecontrol monitor 20 (and an indication thereof may be generated) thatcoming off location by the unit 2 should be undertaken when, forexample, the processor 26 determines that the metocean conditions areless than or equal to at least one value (e.g., one or more sets oflimiting values as the allowable criteria for coming off location, whichmay be selected as representative of the most onerous condition).Likewise, a determination may be made by the control monitor 20 (and anindication thereof may be generated) that coming off location by theunit 2 should not be undertaken when, for example, the processor 26determines the metocean conditions are greater than or equal to at leastone value (e.g., one or more sets of limiting values as the allowablecriteria for coming off location, which may be selected asrepresentative of the most onerous condition).

The control monitor 20 may generate an indication (via GUI 62) ofwhether the measured metocean conditions are acceptable. The GUI 62 may,thus, represent whether conditions are acceptable to come off locationvia a status indicator, which may include text, color, or anotherindicator to provide positive or negative feedback as to whether theunit 2 can come off location. Auditory indications may also accompanythe status indicator to further aid in recognition of the feasibility ofcoming off location. Additionally, the indicator may indicate thatautomatic control and/or retraction of the legs 4 has begun in a comingoff location operation, if the process of coming off location isautomated and/or mechanically controlled. In addition to generating andtransmitting a signal that controls the status indicator, the controlsystem 22 may control the automated coming off location of the unit 2either directly (e.g., via generation and transmission of one or morecontrol signals) or via transmission of a start signal or anauthorization signal to a jacking system of the unit 2, for example, tocontrol or to be utilized in the control of the jacking system and/or asa safety control of the jacking system.

This written description uses examples to disclose the above descriptionto enable any person skilled in the art to practice the disclosure,including making and using any devices or systems and performing anyincorporated methods. The patentable scope of the disclosure is definedby the claims, and may include other examples that occur to thoseskilled in the art. Such other examples are intended to be within thescope of the claims if they have structural elements that do not differfrom the literal language of the claims, or if they include equivalentstructural elements with insubstantial differences from the literallanguages of the claims. Accordingly, while the above disclosedembodiments may be susceptible to various modifications and alternativeforms, specific embodiments have been shown by way of example in thedrawings and have been described in detail herein. However, it should beunderstood that the embodiments are not intended to be limited to theparticular forms disclosed. Rather, the disclosed embodiment are tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the embodiments as defined by the followingappended claims.

What is claimed is:
 1. A device, comprising: an interface configured toreceive a signal indicative of a measured motion of an offshore unitwhen the offshore unit is disposed in an afloat mode in which legs ofthe offshore unit are disposed above a seabed; a memory configured tostore a set of values corresponding to acceptable motions of theoffshore unit when the offshore unit is in the afloat mode; and aprocessor configured to: determine if the measured motion of theoffshore unit indicated by the signal exceeds at least one value of theset of values; and generate an indication to begin a going on locationoperation by the offshore unit inclusive of transitioning the offshoreunit from the afloat mode to an elevated mode of the offshore unit inwhich the legs of the offshore unit are coupled to the seabed when theprocessor determines that the measured motion of the offshore unit isless than or equal to the at least one value.
 2. The device of claim 1,wherein the processor is configured to generate a second indication thatgoing on location by the offshore unit should not be undertaken when theprocessor determines that the measured motion of the offshore unit isgreater than the at least one value.
 3. The device of claim 1, whereinthe interface is configured to receive the set of values as apredetermined set of values corresponding to at least one physicalcharacteristic of the offshore unit.
 4. The device of claim 1, whereinthe interface is configured to receive the set of values as apredetermined set of values corresponding to environmental conditions.5. The device of claim 1, wherein the processor is configured todetermine the measured motion of the offshore unit based on the signal.6. The device of claim 1, comprising a display configured to display agraphical user interface (GUI), wherein the processor is configured totransmit the indication to the display for display thereon inconjunction with the GUI.
 7. The device of claim 1, wherein theindication is configured to initiate control of an automatedimplementation of the going on location operation.
 8. A system,comprising: a sensor configured to measure motions of an offshore unitwhen the offshore unit is disposed in an afloat mode in which legs ofthe offshore unit are disposed above a seabed and generate a signalindicative of the measured motions of the offshore unit; and a controlmonitor configured to be coupled to the sensor, wherein the controlmonitor comprises: an interface configured to receive the signalindicative of the measured motions of an offshore unit; a memoryconfigured to store a set of values corresponding to acceptable motionsof at least one portion of the offshore unit when the offshore unit isin the afloat mode; and a processor configured to: determine if themeasured motions of at least one portion of the offshore unit indicatedby the signal exceeds at least one value of the set of values; andgenerate an indication to begin a going on location operation by theoffshore unit inclusive of transitioning the offshore unit from theafloat mode to an elevated mode of the offshore unit in which the legsof the offshore unit are coupled to the seabed when the processordetermines that the the measured motions of the at least one portion ofthe offshore unit is less than or equal to the at least one value. 9.The system of claim 8, wherein the processor is configured to determinethe motion of the at least one portion of the offshore unit as motion ofa hull of the offshore unit based on the signal.
 10. The system of claim8, wherein the processor is configured to determine the motion of the atleast one portion of the offshore unit as motion of a leg of theoffshore unit based on the signal.
 11. The system of claim 8, whereinthe processor is configured to determine the motion of the at least oneportion of the offshore unit as motion of a footing of the offshore unitbased on the signal.
 12. The system of claim 8, wherein the processor isconfigured to generate an indication that going on location by theoffshore unit should not be undertaken when the processor determinesthat the motion of the offshore unit is greater than the at least onevalue.
 13. The system of claim 8, wherein the control monitor isconfigured to transmit a control signal or a start signal to a jackingsystem of the offshore unit in response to generation of the indicationto control an aspect of operation of the jacking system or initiateoperation of the jacking system.
 14. The system of claim 8, comprising adisplay separate from and coupled to the control monitor and configuredto display a graphical user interface (GUI), wherein the display isconfigured to receive the indication for display thereon in conjunctionwith the GUI.
 15. The system of claim 8, wherein the control monitorcomprises a display configured to display a GUI, wherein the processoris configured to transmit the indication to the display for displaythereon in conjunction with the GUI.
 16. A tangible non-transitorycomputer-readable medium having computer executable code stored thereon,the code comprising instructions to cause a processor to: receive asignal indicative of motion of an offshore unit when the offshore unitis disposed in an afloat mode in which legs of the offshore unit aredisposed above a seabed; receive a predetermined value corresponding toacceptable motions of the offshore unit when the offshore unit is in theafloat mode; determine if the motion of the offshore unit indicated bythe signal exceeds the predetermined value; and generate an indicationto begin a going on location operation by the offshore unit inclusive oftransitioning the offshore unit from the afloat mode to an elevated modeof the offshore unit in which the legs of the offshore unit are coupledto the seabed when the processor determines that the motion of theoffshore unit is less than or equal to the at least one value.
 17. Thetangible non-transitory computer-readable medium of claim 16, whereinthe code comprises instructions to generate a graphical user interface(GUI) to be displayed on the display.
 18. The tangible non-transitorycomputer-readable medium of claim 17, wherein the code comprisesinstructions to generate a status indicator in conjunction with the GUI,wherein the status indicator represents the generated indication thatgoing on location by the offshore unit can be undertaken.
 19. Thetangible non-transitory computer-readable medium of claim 17, whereinthe code comprises instructions to receive user input via in conjunctionwith the GUI, wherein the user input is related to at least onecondition of the offshore unit or at least one environmental condition.20. The tangible non-transitory computer-readable medium of claim 17,wherein the code comprises instructions to generate a representation ofthe motion of the offshore unit in conjunction with the GUI.